1. Field of the Invention
The present invention relates to a wireless tag information management device that devises controlling electric wave radiation by a reader/writer of an information management device that communicates with wireless tags.
2. Description of the Related Art
Recently, wireless tags being wireless data carriers, each of which has set up therein inherent ID, has a memory area in which information can be rewritten, and can identify its inherent ID or write and read out the information in a noncontact manner using an electric wave signal, are coming into use.
For example, mail articles and deliveries are made to have attached thereto or built therein a wireless tag having set up therein inherent ID respectively. Accordingly, those mail articles and deliveries can be identified by transmitting and receiving a communication electric wave signal respectively from a reader/writer arranged at the pathway when they are transported. Furthermore, documents and books are made to have attached thereto a wireless tag. Then, a reader/writer that transmits and receives an electric wave signal similarly can detect whether or not an intended article exists among those multiple stored documents and books.
Generally, a conventional reader/writer that transmits and receives a communication electric wave signal carries out system processing for communication by always radiating a power electric wave for activating wireless tags located in the communication area and a signal electric wave of communication information, or radiating such electric waves during a time period set up by a host device of an entire system, from an antenna of the reader/writer.
Under above-described conventional system technique for communicating with wireless tags, a reader/writer keeps on radiating an electric wave during a set up communication time period irrespective of the existence or nonexistence of wireless tag, that is, even if there is no wireless tag. Such electric wave radiation leads to wasteful power consumption, which is a problem.